In prior-art gas turbine units (Ch. Lechner/J. Seume, Stationäre Gasturbinen [Stationary Gas Turbines], Springer-Verlag, 2003, pages 720–723), the thrust bearing used to axially fix the rotor is arranged in the intake area of the compressor part. This arrangement was always selected because the space requirement is comparatively favorable in the intake area of the compressor part and the thrust bearing is accessible there in a relatively simple manner. Since the thrust bearing requires considerably more oil than the radial journal bearing, the oil feed and oil drain lines can be accommodated in the intake area of the compressor part in a comparatively simple manner.
The components are heated during the operation of the gas turbine. The difference in the heating of the components leads to relative axial displacements between the rotor components and the stator components of the gas turbine. The relative axial displacements increase with increasing distance between the turbine components and the thrust bearing and lead to an increase in clearance between the rotor blade and the stator wall during the transition from the nonoperating state to the operating state of the gas turbine in case of shroudless and conical blades.